As environmental concerns drive shifts in construction materials,rock is increasingly considered as an alternative to sand,reinforcing the importance of understanding its dynamic properties.This study investigates the...As environmental concerns drive shifts in construction materials,rock is increasingly considered as an alternative to sand,reinforcing the importance of understanding its dynamic properties.This study investigates the effect of water content on the small-strain dynamic properties of basalt samples using free-free laboratory testing.Free-free testing,which requires minimal equipment and preparation,provides an efficient and low-cost method for determining key dynamic properties,including three wave velocities(V_(s),V_(p),and V_(c)),material damping ratios,and Poisson's ratios.These properties are crucial for numerical modeling in earthquake analyses and geotechnical site characterization.The test consists of three components:(1)direct travel-time measurement,(2)torsional resonance testing,and(3)compressional resonance testing.A total of 20 rock samples were tested under systematically controlled water contents,ranging from fully dried to saturated,to quantify the effects on Poisson's ratio and material damping ratios.The results showed significant increases in both parameters with rising water content.The Poisson's ratio increased by up to 320%for aphanitic basalt and 150%for vesicular basalt,while the damping ratio rose up to 30-fold(D_(c,min))and 16-fold(D_(s,min)).These findings highlight the critical need to incorporate consideration of water content when characterizing dynamic rock properties for seismic and geotechnical analyses.The practical applicability of this research lies in improving in situ property interpretation and enhancing seismic design reliability by providing engineers with precise relationships between water content and dynamic rock behavior.展开更多
The rigid, perfectly plastic dynamic response of a free-free beam subjected to impact by a projectile at any cross-section is studied. The instantaneous deformations of the beam are given through an analysis of the ...The rigid, perfectly plastic dynamic response of a free-free beam subjected to impact by a projectile at any cross-section is studied. The instantaneous deformations of the beam are given through an analysis of the complete solution for rigid plastic structures. The in?uence of some parameters such as the input energy and mass ratio on the plastic deformation, travelling plastic hinge position and energy partitioning of the beam are discussed.展开更多
安徽大学强光磁试验装置由一台红外自由电子激光装置与六个实验站组成,其中自由电子激光装置控制系统采用实验物理与工业控制系统(Experimental Physics and Industrial Control System,EPICS)作为开发框架。基于EPICS分布式控制架构,...安徽大学强光磁试验装置由一台红外自由电子激光装置与六个实验站组成,其中自由电子激光装置控制系统采用实验物理与工业控制系统(Experimental Physics and Industrial Control System,EPICS)作为开发框架。基于EPICS分布式控制架构,对安徽大学自由电子激光装置各子系统控制进行了详细的设计研究。在控制系统网络部署方面,引入虚拟局域网(Virtual Local Area Network,VLAN)技术构建运行环境,显著提升了系统可靠性与部署效率。目前已完成开发的系统运行表明,该控制系统具有运行高效、稳定可靠等特点,其设计思路和实施方法可为同类控制系统的开发提供参考。展开更多
文摘As environmental concerns drive shifts in construction materials,rock is increasingly considered as an alternative to sand,reinforcing the importance of understanding its dynamic properties.This study investigates the effect of water content on the small-strain dynamic properties of basalt samples using free-free laboratory testing.Free-free testing,which requires minimal equipment and preparation,provides an efficient and low-cost method for determining key dynamic properties,including three wave velocities(V_(s),V_(p),and V_(c)),material damping ratios,and Poisson's ratios.These properties are crucial for numerical modeling in earthquake analyses and geotechnical site characterization.The test consists of three components:(1)direct travel-time measurement,(2)torsional resonance testing,and(3)compressional resonance testing.A total of 20 rock samples were tested under systematically controlled water contents,ranging from fully dried to saturated,to quantify the effects on Poisson's ratio and material damping ratios.The results showed significant increases in both parameters with rising water content.The Poisson's ratio increased by up to 320%for aphanitic basalt and 150%for vesicular basalt,while the damping ratio rose up to 30-fold(D_(c,min))and 16-fold(D_(s,min)).These findings highlight the critical need to incorporate consideration of water content when characterizing dynamic rock properties for seismic and geotechnical analyses.The practical applicability of this research lies in improving in situ property interpretation and enhancing seismic design reliability by providing engineers with precise relationships between water content and dynamic rock behavior.
基金Project supported by the National Natural Science Foundation of China (No.10272011).
文摘The rigid, perfectly plastic dynamic response of a free-free beam subjected to impact by a projectile at any cross-section is studied. The instantaneous deformations of the beam are given through an analysis of the complete solution for rigid plastic structures. The in?uence of some parameters such as the input energy and mass ratio on the plastic deformation, travelling plastic hinge position and energy partitioning of the beam are discussed.
文摘安徽大学强光磁试验装置由一台红外自由电子激光装置与六个实验站组成,其中自由电子激光装置控制系统采用实验物理与工业控制系统(Experimental Physics and Industrial Control System,EPICS)作为开发框架。基于EPICS分布式控制架构,对安徽大学自由电子激光装置各子系统控制进行了详细的设计研究。在控制系统网络部署方面,引入虚拟局域网(Virtual Local Area Network,VLAN)技术构建运行环境,显著提升了系统可靠性与部署效率。目前已完成开发的系统运行表明,该控制系统具有运行高效、稳定可靠等特点,其设计思路和实施方法可为同类控制系统的开发提供参考。
